A 3D-printed hand-held visible spectrophotometric detector for point-of-care uric acid detection

Urinary uric acid measurement is an important tool for clinical screening and differential diagnosis of diseases such as gout and hyperuricemia. To overcome the limitations of the traditional phosphotungstic acid colorimetric method which requires the use of expensive and bulky UV-Vis spectrophotometers, this study employed 3D photopolymerization printing technology to fabricate a hand-held visible spectrophotometer for the quantitative determination of uric acid concentration in human urine. The device integrates an LED light source, a bandpass filter, a 3D-printed detection cell, a silicon photodiode, and a high-precision voltmeter. Its analytical performance was evaluated using methylene blue and phosphate solutions, followed by quantitative determination of uric acid. The device is not only compact and portable but also low-cost. Within the appropriate concentration range, the device demonstrated excellent linear correlation (R² > 0.99) and a low relative standard deviation (RSD). Bland-Altman analysis confirmed the consistency of the measurement results with those obtained using a commercial UV-Vis spectrophotometer. Analysis of the recovery rates for the uric acid test kit revealed that recovery rates at low, medium, and high spiked concentrations ranged from 92% to 104%, and the relative standard deviation (RSD) from three replicate measurements was less than 5% in all cases, indicating high stability of the device. Furthermore, specificity tests conducted on three potential interferents present in urine demonstrated that the method possesses high specificity. This detection device enables rapid point-of-care testing (POCT) for uric acid levels in urine and holds broad application prospects in community clinics and home self-testing scenarios.